1. The Field of the Invention
This application is directed to methods and devices for delivering medical and dental compositions. More particularly, the application is directed to delivery tips for delivering multi-part medical and dental compositions and accessories relating thereto.
2. Relevant Technology
Many modern formulations are packaged in two parts, often known as "A/B components" or "first and second materials". Upon mixing, these A/B components typically undergo a chemical reaction which causes the resultant composition to "set up" in some desired manner, for example, by forming a hardened material. In the dental field, for example, several two-part formulations currently enjoy wide use, such as glass ionomer cements and resinous luting cements. Dental impression materials are also typically made using A/B components.
In order to function properly, it is important that the A/B components of these two component systems be separated until it is desired to mix the components. Typical techniques for retaining A/B type materials in a separated state before mixing the materials include loading the A/B materials into two-part material delivery apparatuses having separate side-by-side barrels or tubes. The side-by-side barrels are each configured to receive a separate material therein and deliver the separate material therefrom.
Examples of such two-part material delivery apparatuses having side-by-side barrels are disclosed in U.S. Pat. Nos. 5,290,259; 5,328,462; 5,643,206; 5,665,066; and 5,697,903, assigned to Ultradent Products, Inc., each of which are incorporated by reference herein.
A wide variety of such two-part material delivery apparatuses exist. Such apparatuses typically have a proximal material receiving end, and a distal delivery end. The distal delivery end typically features first and second openings which are adjacent one another and which are located at the end of neighboring barrels. Material delivered from one of the adjacent openings is typically delivered next to and in parallel relationship with the material delivered from the other opening.
Upon delivery of the first and second materials through the adjacent openings, the practitioner can then mix the materials in a mixing bowl, syringe, mixer or other device. Although mixing of the A/B materials is the ultimate goal of A/B type delivery systems, premature mixing and hardening of material is generally detrimental.
Nevertheless, in typical A/B type delivery systems, it is common for a certain amount of undesired commingling of A/B type materials to occur as the A/B materials exit the adjacent first and second openings. Sometimes, some of the mixed material contacts the distal delivery end of the delivery system, such as by depositing on one of the edges of the proximal and distal openings. Such mixed material tends to harden on the delivery system.
If mixed material hardens in an opening, the hardened material can block or impede the flow path of a barrel. The disruption of the normal flow pattern can cause additional mixing and hardening in undesired areas. Thus, the buildup of reactive A/B materials on the distal end of a delivery system can slow, stop, or otherwise disrupt the delivery of the materials through the system.
The problem of material build up becomes particularly acute when a delivery system is used, then temporarily set aside or stored before a subsequent use. This allows time for mixed materials to harden before the subsequent use.
Another problem associated with the delivery of A/B materials is that uncovered delivery ends can dry out or become inadvertently contaminated. While it is possible to cover delivery ends with a cap, such caps can become readily separated from the delivery system and lost. Furthermore, it can be difficult to achieve a reliable seal between a delivery tip and a two-part material delivery apparatus which delivers material to the delivery tip, thereby allowing seepage of material at the junction between the tip and the two-part material delivery apparatus.
There is, therefore, a need in the art for a system for delivering A and B type materials which keeps the materials separate until mixing is desired and thereby avoids cross-contamination and hardening of the materials until the desired time. Specifically, there is a need in the art for a system which avoids cross-contamination between an A and a B material at a distal delivery end of the system.
There is also a need in the art for an improved seal between material delivery systems and delivery tips. Furthermore, there is a need in the art for an improved system for covering the end of a delivery tip.